A conventional ink-jet cartridge is provided with or mounted on an ejecting device. By means of the ejecting device, the ink within the ink-jet cartridge is ejected and printed onto a substrate. However, in order to stably deliver ink with no ink leakage in the ink-jet printing process by the ejecting device, a negative pressure regulating device and an air filling unit are provided within the ink-jet cartridge, for example, as disclosed in U.S. Pat. Nos. 5,409,134 and 5,541,632. This way provides smooth ink delivery without ink leakage, but an additional negative pressure regulating device and an air filling unit are provided. The structures disclosed in these prior art patents are rather complicated and the precision thereof must be quite high. Therefore, its production cost is relatively high.
Another conventional ink-jet cartridge is provided with an absorptive material, such as a sponge, to prevent ink leakage
However, in this conventional ink-jet cartridge, the entire room within the inkjet cartridge has to be filled with a sponge in order to obtain a good effect of zero ink leakage. Only 60% of the ink within the conventional ink-jet cartridge can be ejected and the remaining ink is kept by the sponge and cannot be ejected. Therefore, it becomes a waste of material.